# m为指数, n为求和项数
def sumK(m,n):
    total_sum = 0
    for i in range(1, n + 1):
        total_sum += i ** m
    return round(total_sum)

if __name__ == '__main__':
    a = eval(input())
    b = eval(input())
    c = eval(input())
    print(sumK(1,a)+sumK(2,b)+sumK(-1,c))
